Experimental and numerical investigation on the flow and heat transfer characteristics in a tree-like branching microchannel

A T-shaped tree-like branching microchannel is designed for gas turbine blade cooling. The conjugate heat transfer characteristics of air coolant are investigated experimentally. To compare the flow and thermal performance of steam and air coolant numerically, the SSG turbulence model is adopted. The results reveal that the heat transfer coefficient is gradually increased through the whole branching microchannel. The conjugate heat transfer effects lead to a heat transfer suppression in the entrance region but an enhancement in the channel terminal region. The flow and heat transfer trend of steam and air are similar, however, compare to air, steam has a 49.2 % higher average Nusselt number and 31.8 % lower friction factor under the same inlet mass flow rate. Under a low mass flow rate condition, the steam cooling shows a smaller maximum temperature difference and better uniform cooling performance.